├── .gitignore ├── Dockerfile ├── LICENSE ├── Makefile ├── README.md ├── scripts └── build-kernel.sh └── src ├── char_simple.c ├── hello-2.c ├── hello-3.c ├── hello_simple.c ├── jiffies_1.c ├── led.c ├── led.h ├── null_pointer.c ├── timer_hiresolution.c └── timer_simple.c /.gitignore: -------------------------------------------------------------------------------- 1 | *.o 2 | *.ko 3 | *cmd 4 | *.swp 5 | *mod* 6 | *.symvers 7 | -------------------------------------------------------------------------------- /Dockerfile: -------------------------------------------------------------------------------- 1 | FROM centos:latest 2 | 3 | RUN yum -y groupinstall "Development Tools" 4 | RUN yum -y install ncurses-devel \ 5 | hmaccalc \ 6 | zlib-devel \ 7 | binutils-devel \ 8 | elfutils-libelf-devel \ 9 | bc \ 10 | openssl-devel \ 11 | kernel-devel \ 12 | kernel-headers 13 | 14 | COPY scripts/build-kernel.sh / 15 | CMD /build-kernel.sh 16 | # copy from linux/ the generated uimage to your mount volume 17 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 2, June 1991 3 | 4 | Copyright (C) 1989, 1991 Free Software Foundation, Inc., 5 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 6 | Everyone is permitted to copy and distribute verbatim copies 7 | of this license document, but changing it is not allowed. 8 | 9 | Preamble 10 | 11 | The licenses for most software are designed to take away your 12 | freedom to share and change it. By contrast, the GNU General Public 13 | License is intended to guarantee your freedom to share and change free 14 | software--to make sure the software is free for all its users. This 15 | General Public License applies to most of the Free Software 16 | Foundation's software and to any other program whose authors commit to 17 | using it. (Some other Free Software Foundation software is covered by 18 | the GNU Lesser General Public License instead.) You can apply it to 19 | your programs, too. 20 | 21 | When we speak of free software, we are referring to freedom, not 22 | price. Our General Public Licenses are designed to make sure that you 23 | have the freedom to distribute copies of free software (and charge for 24 | this service if you wish), that you receive source code or can get it 25 | if you want it, that you can change the software or use pieces of it 26 | in new free programs; and that you know you can do these things. 27 | 28 | To protect your rights, we need to make restrictions that forbid 29 | anyone to deny you these rights or to ask you to surrender the rights. 30 | These restrictions translate to certain responsibilities for you if you 31 | distribute copies of the software, or if you modify it. 32 | 33 | For example, if you distribute copies of such a program, whether 34 | gratis or for a fee, you must give the recipients all the rights that 35 | you have. You must make sure that they, too, receive or can get the 36 | source code. And you must show them these terms so they know their 37 | rights. 38 | 39 | We protect your rights with two steps: (1) copyright the software, and 40 | (2) offer you this license which gives you legal permission to copy, 41 | distribute and/or modify the software. 42 | 43 | Also, for each author's protection and ours, we want to make certain 44 | that everyone understands that there is no warranty for this free 45 | software. If the software is modified by someone else and passed on, we 46 | want its recipients to know that what they have is not the original, so 47 | that any problems introduced by others will not reflect on the original 48 | authors' reputations. 49 | 50 | Finally, any free program is threatened constantly by software 51 | patents. We wish to avoid the danger that redistributors of a free 52 | program will individually obtain patent licenses, in effect making the 53 | program proprietary. To prevent this, we have made it clear that any 54 | patent must be licensed for everyone's free use or not licensed at all. 55 | 56 | The precise terms and conditions for copying, distribution and 57 | modification follow. 58 | 59 | GNU GENERAL PUBLIC LICENSE 60 | TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 61 | 62 | 0. This License applies to any program or other work which contains 63 | a notice placed by the copyright holder saying it may be distributed 64 | under the terms of this General Public License. The "Program", below, 65 | refers to any such program or work, and a "work based on the Program" 66 | means either the Program or any derivative work under copyright law: 67 | that is to say, a work containing the Program or a portion of it, 68 | either verbatim or with modifications and/or translated into another 69 | language. (Hereinafter, translation is included without limitation in 70 | the term "modification".) Each licensee is addressed as "you". 71 | 72 | Activities other than copying, distribution and modification are not 73 | covered by this License; they are outside its scope. The act of 74 | running the Program is not restricted, and the output from the Program 75 | is covered only if its contents constitute a work based on the 76 | Program (independent of having been made by running the Program). 77 | Whether that is true depends on what the Program does. 78 | 79 | 1. You may copy and distribute verbatim copies of the Program's 80 | source code as you receive it, in any medium, provided that you 81 | conspicuously and appropriately publish on each copy an appropriate 82 | copyright notice and disclaimer of warranty; keep intact all the 83 | notices that refer to this License and to the absence of any warranty; 84 | and give any other recipients of the Program a copy of this License 85 | along with the Program. 86 | 87 | You may charge a fee for the physical act of transferring a copy, and 88 | you may at your option offer warranty protection in exchange for a fee. 89 | 90 | 2. You may modify your copy or copies of the Program or any portion 91 | of it, thus forming a work based on the Program, and copy and 92 | distribute such modifications or work under the terms of Section 1 93 | above, provided that you also meet all of these conditions: 94 | 95 | a) You must cause the modified files to carry prominent notices 96 | stating that you changed the files and the date of any change. 97 | 98 | b) You must cause any work that you distribute or publish, that in 99 | whole or in part contains or is derived from the Program or any 100 | part thereof, to be licensed as a whole at no charge to all third 101 | parties under the terms of this License. 102 | 103 | c) If the modified program normally reads commands interactively 104 | when run, you must cause it, when started running for such 105 | interactive use in the most ordinary way, to print or display an 106 | announcement including an appropriate copyright notice and a 107 | notice that there is no warranty (or else, saying that you provide 108 | a warranty) and that users may redistribute the program under 109 | these conditions, and telling the user how to view a copy of this 110 | License. (Exception: if the Program itself is interactive but 111 | does not normally print such an announcement, your work based on 112 | the Program is not required to print an announcement.) 113 | 114 | These requirements apply to the modified work as a whole. If 115 | identifiable sections of that work are not derived from the Program, 116 | and can be reasonably considered independent and separate works in 117 | themselves, then this License, and its terms, do not apply to those 118 | sections when you distribute them as separate works. But when you 119 | distribute the same sections as part of a whole which is a work based 120 | on the Program, the distribution of the whole must be on the terms of 121 | this License, whose permissions for other licensees extend to the 122 | entire whole, and thus to each and every part regardless of who wrote it. 123 | 124 | Thus, it is not the intent of this section to claim rights or contest 125 | your rights to work written entirely by you; rather, the intent is to 126 | exercise the right to control the distribution of derivative or 127 | collective works based on the Program. 128 | 129 | In addition, mere aggregation of another work not based on the Program 130 | with the Program (or with a work based on the Program) on a volume of 131 | a storage or distribution medium does not bring the other work under 132 | the scope of this License. 133 | 134 | 3. You may copy and distribute the Program (or a work based on it, 135 | under Section 2) in object code or executable form under the terms of 136 | Sections 1 and 2 above provided that you also do one of the following: 137 | 138 | a) Accompany it with the complete corresponding machine-readable 139 | source code, which must be distributed under the terms of Sections 140 | 1 and 2 above on a medium customarily used for software interchange; or, 141 | 142 | b) Accompany it with a written offer, valid for at least three 143 | years, to give any third party, for a charge no more than your 144 | cost of physically performing source distribution, a complete 145 | machine-readable copy of the corresponding source code, to be 146 | distributed under the terms of Sections 1 and 2 above on a medium 147 | customarily used for software interchange; or, 148 | 149 | c) Accompany it with the information you received as to the offer 150 | to distribute corresponding source code. (This alternative is 151 | allowed only for noncommercial distribution and only if you 152 | received the program in object code or executable form with such 153 | an offer, in accord with Subsection b above.) 154 | 155 | The source code for a work means the preferred form of the work for 156 | making modifications to it. For an executable work, complete source 157 | code means all the source code for all modules it contains, plus any 158 | associated interface definition files, plus the scripts used to 159 | control compilation and installation of the executable. However, as a 160 | special exception, the source code distributed need not include 161 | anything that is normally distributed (in either source or binary 162 | form) with the major components (compiler, kernel, and so on) of the 163 | operating system on which the executable runs, unless that component 164 | itself accompanies the executable. 165 | 166 | If distribution of executable or object code is made by offering 167 | access to copy from a designated place, then offering equivalent 168 | access to copy the source code from the same place counts as 169 | distribution of the source code, even though third parties are not 170 | compelled to copy the source along with the object code. 171 | 172 | 4. You may not copy, modify, sublicense, or distribute the Program 173 | except as expressly provided under this License. Any attempt 174 | otherwise to copy, modify, sublicense or distribute the Program is 175 | void, and will automatically terminate your rights under this License. 176 | However, parties who have received copies, or rights, from you under 177 | this License will not have their licenses terminated so long as such 178 | parties remain in full compliance. 179 | 180 | 5. You are not required to accept this License, since you have not 181 | signed it. However, nothing else grants you permission to modify or 182 | distribute the Program or its derivative works. These actions are 183 | prohibited by law if you do not accept this License. Therefore, by 184 | modifying or distributing the Program (or any work based on the 185 | Program), you indicate your acceptance of this License to do so, and 186 | all its terms and conditions for copying, distributing or modifying 187 | the Program or works based on it. 188 | 189 | 6. Each time you redistribute the Program (or any work based on the 190 | Program), the recipient automatically receives a license from the 191 | original licensor to copy, distribute or modify the Program subject to 192 | these terms and conditions. You may not impose any further 193 | restrictions on the recipients' exercise of the rights granted herein. 194 | You are not responsible for enforcing compliance by third parties to 195 | this License. 196 | 197 | 7. If, as a consequence of a court judgment or allegation of patent 198 | infringement or for any other reason (not limited to patent issues), 199 | conditions are imposed on you (whether by court order, agreement or 200 | otherwise) that contradict the conditions of this License, they do not 201 | excuse you from the conditions of this License. If you cannot 202 | distribute so as to satisfy simultaneously your obligations under this 203 | License and any other pertinent obligations, then as a consequence you 204 | may not distribute the Program at all. For example, if a patent 205 | license would not permit royalty-free redistribution of the Program by 206 | all those who receive copies directly or indirectly through you, then 207 | the only way you could satisfy both it and this License would be to 208 | refrain entirely from distribution of the Program. 209 | 210 | If any portion of this section is held invalid or unenforceable under 211 | any particular circumstance, the balance of the section is intended to 212 | apply and the section as a whole is intended to apply in other 213 | circumstances. 214 | 215 | It is not the purpose of this section to induce you to infringe any 216 | patents or other property right claims or to contest validity of any 217 | such claims; this section has the sole purpose of protecting the 218 | integrity of the free software distribution system, which is 219 | implemented by public license practices. Many people have made 220 | generous contributions to the wide range of software distributed 221 | through that system in reliance on consistent application of that 222 | system; it is up to the author/donor to decide if he or she is willing 223 | to distribute software through any other system and a licensee cannot 224 | impose that choice. 225 | 226 | This section is intended to make thoroughly clear what is believed to 227 | be a consequence of the rest of this License. 228 | 229 | 8. If the distribution and/or use of the Program is restricted in 230 | certain countries either by patents or by copyrighted interfaces, the 231 | original copyright holder who places the Program under this License 232 | may add an explicit geographical distribution limitation excluding 233 | those countries, so that distribution is permitted only in or among 234 | countries not thus excluded. In such case, this License incorporates 235 | the limitation as if written in the body of this License. 236 | 237 | 9. The Free Software Foundation may publish revised and/or new versions 238 | of the General Public License from time to time. Such new versions will 239 | be similar in spirit to the present version, but may differ in detail to 240 | address new problems or concerns. 241 | 242 | Each version is given a distinguishing version number. If the Program 243 | specifies a version number of this License which applies to it and "any 244 | later version", you have the option of following the terms and conditions 245 | either of that version or of any later version published by the Free 246 | Software Foundation. If the Program does not specify a version number of 247 | this License, you may choose any version ever published by the Free Software 248 | Foundation. 249 | 250 | 10. If you wish to incorporate parts of the Program into other free 251 | programs whose distribution conditions are different, write to the author 252 | to ask for permission. For software which is copyrighted by the Free 253 | Software Foundation, write to the Free Software Foundation; we sometimes 254 | make exceptions for this. Our decision will be guided by the two goals 255 | of preserving the free status of all derivatives of our free software and 256 | of promoting the sharing and reuse of software generally. 257 | 258 | NO WARRANTY 259 | 260 | 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY 261 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN 262 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES 263 | PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED 264 | OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 265 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS 266 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE 267 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, 268 | REPAIR OR CORRECTION. 269 | 270 | 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 271 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR 272 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, 273 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING 274 | OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED 275 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY 276 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER 277 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE 278 | POSSIBILITY OF SUCH DAMAGES. 279 | 280 | END OF TERMS AND CONDITIONS 281 | 282 | How to Apply These Terms to Your New Programs 283 | 284 | If you develop a new program, and you want it to be of the greatest 285 | possible use to the public, the best way to achieve this is to make it 286 | free software which everyone can redistribute and change under these terms. 287 | 288 | To do so, attach the following notices to the program. It is safest 289 | to attach them to the start of each source file to most effectively 290 | convey the exclusion of warranty; and each file should have at least 291 | the "copyright" line and a pointer to where the full notice is found. 292 | 293 | {description} 294 | Copyright (C) {year} {fullname} 295 | 296 | This program is free software; you can redistribute it and/or modify 297 | it under the terms of the GNU General Public License as published by 298 | the Free Software Foundation; either version 2 of the License, or 299 | (at your option) any later version. 300 | 301 | This program is distributed in the hope that it will be useful, 302 | but WITHOUT ANY WARRANTY; without even the implied warranty of 303 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 304 | GNU General Public License for more details. 305 | 306 | You should have received a copy of the GNU General Public License along 307 | with this program; if not, write to the Free Software Foundation, Inc., 308 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 309 | 310 | Also add information on how to contact you by electronic and paper mail. 311 | 312 | If the program is interactive, make it output a short notice like this 313 | when it starts in an interactive mode: 314 | 315 | Gnomovision version 69, Copyright (C) year name of author 316 | Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 317 | This is free software, and you are welcome to redistribute it 318 | under certain conditions; type `show c' for details. 319 | 320 | The hypothetical commands `show w' and `show c' should show the appropriate 321 | parts of the General Public License. Of course, the commands you use may 322 | be called something other than `show w' and `show c'; they could even be 323 | mouse-clicks or menu items--whatever suits your program. 324 | 325 | You should also get your employer (if you work as a programmer) or your 326 | school, if any, to sign a "copyright disclaimer" for the program, if 327 | necessary. Here is a sample; alter the names: 328 | 329 | Yoyodyne, Inc., hereby disclaims all copyright interest in the program 330 | `Gnomovision' (which makes passes at compilers) written by James Hacker. 331 | 332 | {signature of Ty Coon}, 1 April 1989 333 | Ty Coon, President of Vice 334 | 335 | This General Public License does not permit incorporating your program into 336 | proprietary programs. If your program is a subroutine library, you may 337 | consider it more useful to permit linking proprietary applications with the 338 | library. If this is what you want to do, use the GNU Lesser General 339 | Public License instead of this License. 340 | 341 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | ifeq ($(strip $(MODULE)),) 2 | obj-m += src/hello_simple.o 3 | else 4 | obj-m += $(MODULE).o 5 | endif 6 | 7 | 8 | KERNEL_SRC = /lib/modules/$(shell uname -r)/build 9 | 10 | all: 11 | make -C $(KERNEL_SRC) M=$(PWD) modules 12 | 13 | clean: 14 | make -C $(KERNEL_SRC) M=$(PWD) clean 15 | 16 | image: 17 | docker build -t build_kernel . 18 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Linux Device Drivers Tutorial 2 | 3 | Hi, this is a compendium of multiple didactic Linux Kernel modules, I am doing 4 | this due to the fact that many times somebody says that the LDD book is too 5 | complicated, well here is a series of examples that might be helpful. 6 | 7 | In my opinion a really good start for really newbies Linux Modules Developers 8 | WAS (past time on purpose) The Linux Kernel Module Programming Guide 9 | (http://www.tldp.org/LDP/lkmpg/2.6/html/). However, this guide is based on the 10 | Kernel 2.6.. which has many deprecated parts in relationship with the 3.~ 11 | kernel 12 | 13 | Well this project tries to update the source code of that guide to the latest 14 | a version of the kernel (please update and improve as possible), hopefully, if 15 | many folks agree the guide will be updated, just as its authors wanted. 16 | 17 | 18 | ## SET UP: 19 | 20 | * Fedora 21 | 22 | Download all the kernel dev packages (in case of Fedora): 23 | 24 | https://fedoraproject.org/wiki/Building_a_custom_kernel 25 | 26 | You might have some problems with the livna.repo, please temporary remove it 27 | 28 | * CentOS 29 | 30 | In case of CentOS: 31 | 32 | ``` 33 | yum -y groupinstall "Development Tools" 34 | yum -y install ncurses-devel \ 35 | hmaccalc \ 36 | zlib-devel \ 37 | binutils-devel \ 38 | elfutils-libelf-devel \ 39 | bc \ 40 | openssl-devel \ 41 | kernel-devel \ 42 | kernel-headers 43 | ``` 44 | 45 | ### BUILD KERNEL 46 | 47 | If you want to build the kernel we have a Dockerfile image, just run: 48 | 49 | ``` 50 | make iamge 51 | docker run build_kernel:latest 52 | ``` 53 | 54 | Is important to customize a shared volume to copy the kernel uimage, 55 | the build_kernel docker image just build the upstream kernel 56 | (adjust the git clone to your needs) 57 | 58 | 59 | 60 | ## BUILD MODULES: 61 | 62 | 1) make MODULE="" // DO NOT add the .c, just the name of 63 | the module. If no name is passed the makefile will build the basic hello 64 | world module 65 | 66 | 2) make clean: will clean the module 67 | 68 | ## INSTALL MODULES: 69 | 70 | insmod module.ko 71 | modprobe module.ko 72 | 73 | REMOVE: 74 | 75 | rmmod module 76 | 77 | Check printk message: 78 | 79 | dmesg 80 | or 81 | cat /var/log/syslog 82 | 83 | -------------------------------------------------------------------------------- /scripts/build-kernel.sh: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | 3 | echo "hi there" 4 | 5 | git clone --depth 1 https://github.com/torvalds/linux.git 6 | cd /linux/ && yes "" | make oldconfig 7 | cd /linux/ && make 8 | 9 | -------------------------------------------------------------------------------- /src/char_simple.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | // if new versions of kernel (> 4.12 ) #include 5 | #include /* for put_user */ 6 | 7 | #define AUTOR "Victor Rodriguez" 8 | #define DESCRIPCION "Char Driver Hello World" 9 | #define DEVICE_NAME "mychardriver" 10 | #define MAX 1024 11 | 12 | static int num_mayor; 13 | static unsigned long procfs_buffer_size = 0; 14 | static char buffer_data[MAX]; 15 | 16 | static char msg[MAX]; /* The msg the device will give when asked */ 17 | static char *msg_Ptr; 18 | 19 | static int device_open(struct inode *inode, struct file *file); 20 | static int device_release(struct inode *inode, struct file *file); 21 | static ssize_t device_read(struct file *, char *, size_t, loff_t *); 22 | static ssize_t device_write(struct file *, const char *, size_t, loff_t *); 23 | 24 | 25 | static struct file_operations fops= { 26 | .open = device_open, 27 | .release = device_release, 28 | .read = device_read, 29 | .write = device_write, 30 | }; 31 | 32 | 33 | static int __init hola_inicio(void) 34 | { 35 | 36 | printk(KERN_INFO "Hello from the Kernel !!! (how cool is that) \n"); 37 | 38 | /*Ask for a mayor number to the kernel */ 39 | 40 | num_mayor=register_chrdev(0, DEVICE_NAME, &fops); 41 | printk(KERN_INFO "Major Number = %d \n",num_mayor); 42 | printk(KERN_INFO "Name = %s \n",DEVICE_NAME); 43 | printk(KERN_INFO "Generate the device file with\ 44 | mknod /dev/%s c %d 0 \n",DEVICE_NAME,num_mayor); 45 | 46 | return 0 ; 47 | 48 | } 49 | 50 | static void __exit hola_fin(void) 51 | { 52 | unregister_chrdev(num_mayor, DEVICE_NAME); 53 | printk(KERN_INFO "Good Bye , modulo desinstalled \n"); 54 | } 55 | 56 | module_init(hola_inicio); 57 | module_exit(hola_fin); 58 | 59 | 60 | /* Methods */ 61 | 62 | static int device_open(struct inode *inode, struct file *file) 63 | { 64 | sprintf(msg,buffer_data); 65 | msg_Ptr = msg; 66 | return 0; 67 | } 68 | 69 | static int device_release(struct inode *inode, struct file *file) 70 | { 71 | return 0; 72 | } 73 | 74 | static ssize_t device_read(struct file *filp, /* see include/linux/fs.h */ 75 | char *buf, /* buffer to fill with data */ 76 | size_t len, /* length of the buffer */ 77 | loff_t * off) 78 | { 79 | int bytes_read = 0; 80 | 81 | if (*msg_Ptr == 0) 82 | return 0; 83 | 84 | 85 | while (len && *msg_Ptr) { 86 | 87 | /* 88 | * The buffer is in the user data segment, not the kernel 89 | * segment so "*" assignment won't work. We have to use 90 | * put_user which copies data from the kernel data segment to 91 | * the user data segment. 92 | */ 93 | put_user(*(msg_Ptr++), buf++); 94 | 95 | len--; 96 | bytes_read++; 97 | } 98 | 99 | /* 100 | * Most read functions return the number of bytes put into the buffer 101 | */ 102 | return bytes_read; 103 | 104 | 105 | } 106 | 107 | static ssize_t device_write(struct file *filp, 108 | const char *buf, 109 | size_t len, 110 | loff_t * off) 111 | { 112 | 113 | procfs_buffer_size = len; 114 | 115 | if ( copy_from_user(buffer_data, buf, procfs_buffer_size) ) { 116 | return -EFAULT; 117 | } 118 | *off += len; 119 | 120 | pr_info("user input string: %s\n",buffer_data); 121 | pr_info("user input string len: %lu\n",procfs_buffer_size); 122 | 123 | return procfs_buffer_size; 124 | } 125 | 126 | 127 | MODULE_LICENSE("GPL"); 128 | MODULE_AUTHOR(AUTOR); /* Who wrote this module? */ 129 | MODULE_DESCRIPTION(DESCRIPCION); /* What does this module do */ 130 | 131 | /* 132 | * This module uses /dev/mychardriver. The MODULE_SUPPORTED_DEVICE macro might 133 | * be used in the future to help automatic configuration of modules, buti is 134 | * currently unused other than for documentation purposes. 135 | */ 136 | 137 | MODULE_SUPPORTED_DEVICE("mychardriver"); 138 | -------------------------------------------------------------------------------- /src/hello-2.c: -------------------------------------------------------------------------------- 1 | /* 2 | * hello-2.c - Demonstrating the module_init() and module_exit() macros. 3 | * This is preferred over using init_module() and cleanup_module(). 4 | */ 5 | 6 | #include /* Needed by all modules */ 7 | #include /* Needed for KERN_INFO */ 8 | #include /* Needed for the macros */ 9 | 10 | static int __init hello_2_init(void) 11 | { 12 | printk(KERN_INFO "Hello, world 2\n"); 13 | return 0; 14 | } 15 | 16 | static void __exit hello_2_exit(void) 17 | { 18 | printk(KERN_INFO "Goodbye, world 2\n"); 19 | } 20 | 21 | module_init(hello_2_init); 22 | module_exit(hello_2_exit); 23 | -------------------------------------------------------------------------------- /src/hello-3.c: -------------------------------------------------------------------------------- 1 | /* 2 | * hello-3.c - Illustrating the __init, __initdata and __exit macros. 3 | */ 4 | 5 | #include /* Needed by all modules */ 6 | #include /* Needed for KERN_INFO */ 7 | #include /* Needed for the macros */ 8 | 9 | static int hello3_data __initdata = 3; 10 | 11 | static int __init hello_3_init(void) 12 | { 13 | printk(KERN_INFO "Hello, world %d\n", hello3_data); 14 | return 0; 15 | } 16 | 17 | static void __exit hello_3_exit(void) 18 | { 19 | printk(KERN_INFO "Goodbye, world 3\n"); 20 | } 21 | 22 | module_init(hello_3_init); 23 | module_exit(hello_3_exit); 24 | -------------------------------------------------------------------------------- /src/hello_simple.c: -------------------------------------------------------------------------------- 1 | /* 2 | * * hello-1.c - The simplest kernel module. 3 | * */ 4 | #include /* Needed by all modules */ 5 | #include /* Needed for KERN_INFO */ 6 | 7 | int init_module(void) 8 | { 9 | printk(KERN_INFO "Hello world 1.\n"); 10 | 11 | /* 12 | * * A non 0 return means init_module failed; module can't be 13 | * loaded. 14 | * */ 15 | return 0; 16 | } 17 | 18 | void cleanup_module(void) 19 | { 20 | printk(KERN_INFO "Goodbye world 1.\n"); 21 | } 22 | -------------------------------------------------------------------------------- /src/jiffies_1.c: -------------------------------------------------------------------------------- 1 | /* 2 | * hello-1.c - The simplest kernel module. 3 | */ 4 | #include /* Needed by all modules */ 5 | #include /* Needed for KERN_INFO */ 6 | #include 7 | 8 | #define DELAY 3 9 | 10 | int init_module(void) 11 | { 12 | int n = 10; 13 | 14 | printk(KERN_INFO "Hello world 1.\n"); 15 | unsigned long j, stamp_1, stamp_half, stamp_n,jifdone; 16 | j = jiffies; /* read the current value */ 17 | stamp_1 = j + HZ; /* 1 second in the future */ 18 | stamp_half = j + HZ/2; /* half a second */ 19 | stamp_n = j + n * HZ / 1000; /* n milliseconds */ 20 | 21 | printk(KERN_INFO "Current time = %lu \n",j); 22 | printk(KERN_INFO "1 second in the future = %lu \n",stamp_1 ); 23 | printk(KERN_INFO "half a second= %lu \n",stamp_half ); 24 | printk(KERN_INFO "n milliseconds = %lu \n",stamp_n ); 25 | 26 | /* 27 | jifdone = jiffies + DELAY * HZ; 28 | 29 | while ( time_before( jiffies,jifdone)) 30 | { 31 | printk(KERN_INFO "Waiting for Nothing .\n"); 32 | } 33 | */ 34 | return 0; 35 | } 36 | 37 | void cleanup_module(void) 38 | { 39 | printk(KERN_INFO "Goodbye world 1.\n"); 40 | } 41 | -------------------------------------------------------------------------------- /src/led.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | #include /* for put_user */ 5 | #include 6 | #include 7 | 8 | #include "led.h" 9 | 10 | #define AUTOR "Victor Rodriguez" 11 | #define DESCRIPCION "Driver ioctl" 12 | #define MAXIMO 1024 13 | 14 | /*Turn On a Led */ 15 | 16 | 17 | //#define PIN_LED GPIO_TO_PIN(6, 13) 18 | //#define MUX_LED DA850_GPIO6_13 19 | 20 | 21 | #define PIN_LED GPIO_TO_PIN(6, 12) 22 | #define MUX_LED DA850_GPIO6_12 23 | 24 | 25 | /*Varaiables */ 26 | static int status; 27 | static int num_mayor; 28 | static unsigned long procfs_buffer_size = 0; 29 | static char buffer_data[MAXIMO]; 30 | static char msg[MAXIMO]; /* The msg the device will give when asked */ 31 | static char *msg_Ptr; 32 | 33 | /*Metods faile operation*/ 34 | static int device_open(struct inode *inode, struct file *file); 35 | static int device_release(struct inode *inode, struct file *file); 36 | static ssize_t device_read(struct file *, char *, size_t, loff_t *); 37 | static ssize_t device_write(struct file *, const char *, size_t, loff_t *); 38 | static int device_ioctl(struct inode *inode,struct file *file,unsigned int ioctl_num,unsigned long ioctl_param); 39 | 40 | /*Metodos to turn on a led*/ 41 | static int led_on(void); 42 | static int led_off(void); 43 | 44 | /*File operation structure */ 45 | static struct file_operations fops= { 46 | .open = device_open, 47 | .release = device_release, 48 | .read = device_read, 49 | .write = device_write, 50 | .ioctl = device_ioctl, 51 | }; 52 | 53 | 54 | static int __init hola_inicio(void) 55 | { 56 | 57 | 58 | num_mayor=register_chrdev(MAJOR_NUM, DEVICE_NAME, &fops); 59 | printk(KERN_INFO "The mayor number is %d \n",MAJOR_NUM); 60 | printk(KERN_INFO "The minor number is %s \n",DEVICE_NAME); 61 | printk(KERN_INFO "Generete the device driver with mknod %s c %d 0 \n",DEVICE_NAME,MAJOR_NUM); 62 | 63 | return 0 ; 64 | 65 | } 66 | 67 | static void __exit hola_fin(void) 68 | { 69 | unregister_chrdev(num_mayor, DEVICE_NAME); 70 | } 71 | 72 | module_init(hola_inicio); 73 | module_exit(hola_fin); 74 | 75 | 76 | 77 | /*Metods faile operation*/ 78 | 79 | static int device_open(struct inode *inode, struct file *file) 80 | { 81 | sprintf(msg,buffer_data); 82 | msg_Ptr = msg; 83 | return 0; 84 | } 85 | 86 | static int device_release(struct inode *inode, struct file *file) 87 | { 88 | return 0; 89 | } 90 | 91 | static ssize_t device_read(struct file *filp, /* see include/linux/fs.h */ 92 | char *buf, /* buffer to fill with data */ 93 | size_t len, /* length of the buffer */ 94 | loff_t * off) 95 | { 96 | int bytes_read = 0; 97 | 98 | /*Turn on led */ 99 | led_on(); 100 | 101 | if (*msg_Ptr == 0) 102 | return 0; 103 | 104 | 105 | while (len && *msg_Ptr) { 106 | 107 | /* 108 | * The buffer is in the user data segment, not the kernel 109 | * segment so "*" assignment won't work. We have to use 110 | * put_user which copies data from the kernel data segment to 111 | * the user data segment. 112 | */ 113 | put_user(*(msg_Ptr++), buf++); 114 | 115 | len--; 116 | bytes_read++; 117 | } 118 | 119 | /* 120 | * Most read functions return the number of bytes put into the buffer 121 | */ 122 | return bytes_read; 123 | 124 | 125 | } 126 | 127 | static ssize_t device_write(struct file *filp, 128 | const char *buf, 129 | size_t len, 130 | loff_t * off) 131 | { 132 | 133 | procfs_buffer_size = len; 134 | 135 | if ( copy_from_user(buffer_data, buf, procfs_buffer_size) ) { 136 | return -EFAULT; 137 | } 138 | *off += len; 139 | 140 | /*Turn of led */ 141 | led_off(); 142 | return procfs_buffer_size; 143 | } 144 | 145 | int device_ioctl(struct inode *inode, // see include/linux/fs.h 146 | struct file *file, // ditto 147 | unsigned int ioctl_num, // number and param for ioctl 148 | unsigned long ioctl_param) 149 | { 150 | 151 | 152 | switch (ioctl_num) 153 | { 154 | case IOCTL_SET_MSG: 155 | 156 | 157 | if(ioctl_param == 1) 158 | { 159 | led_on(); 160 | } 161 | 162 | if (ioctl_param == 0) 163 | { 164 | led_off(); 165 | } 166 | 167 | break; 168 | 169 | case IOCTL_GET_MSG: 170 | /*Get the value */ 171 | printk(KERN_INFO "Entro en IOCTL_GET_MSG \n"); 172 | status = gpio_get_value(PIN_LED); 173 | printk(KERN_INFO "El valor del pin 6,13 es %d \n", status); 174 | return status; 175 | break; 176 | 177 | } 178 | 179 | return 0; 180 | } 181 | 182 | static int led_on(void) 183 | { 184 | 185 | 186 | int ret; 187 | 188 | /*Free gpio */ 189 | gpio_free(PIN_LED); 190 | 191 | /*Configure in mux.h */ 192 | ret = davinci_cfg_reg (MUX_LED); 193 | if (ret<0) 194 | { 195 | printk(KERN_INFO "No es posible configurar el led 1\n"); 196 | return ret; 197 | } 198 | 199 | /*Ask permision to turn it on */ 200 | ret = gpio_request(PIN_LED, "led"); 201 | if (ret) 202 | { 203 | printk(KERN_INFO "No es posible configurar el led 2\n"); 204 | return ret; 205 | } 206 | 207 | 208 | 209 | /*Configure as out put */ 210 | gpio_direction_output(PIN_LED, 1); 211 | 212 | /*TURN ON */ 213 | gpio_set_value(PIN_LED, 1); 214 | 215 | 216 | return 0 ; 217 | 218 | } 219 | 220 | static int led_off(void) 221 | { 222 | int ret; 223 | 224 | /*Free gpio */ 225 | gpio_free(PIN_LED); 226 | 227 | /*Configure in mux.h */ 228 | ret = davinci_cfg_reg (MUX_LED); 229 | if (ret<0) 230 | { 231 | printk(KERN_INFO "No es posible configurar el led 1\n"); 232 | return ret; 233 | } 234 | 235 | /*Configure as out put */ 236 | ret = gpio_request(PIN_LED, "led"); 237 | if (ret) 238 | { 239 | printk(KERN_INFO "No es posible configurar el led 2\n"); 240 | return ret; 241 | } 242 | 243 | 244 | 245 | /*Configure as out put */ 246 | gpio_direction_output(PIN_LED, 1); 247 | 248 | /*TURN OFF */ 249 | gpio_set_value(PIN_LED, 0); 250 | 251 | 252 | return 0 ; 253 | 254 | } 255 | 256 | MODULE_LICENSE("GPL"); 257 | MODULE_AUTHOR(AUTOR); /* Who wrote this module? */ 258 | MODULE_DESCRIPTION(DESCRIPCION); /* What does this module do */ 259 | MODULE_SUPPORTED_DEVICE("ioctl-hawkboard"); 260 | -------------------------------------------------------------------------------- /src/led.h: -------------------------------------------------------------------------------- 1 | #ifndef LEDDEV_H 2 | #define LEDDEV_H 3 | 4 | #include 5 | 6 | #define MAJOR_NUM 100 7 | #define DEVICE_NAME "ioctl_led_hawkboard" 8 | 9 | #define IOCTL_SET_MSG _IOR(MAJOR_NUM, 0, char *) 10 | #define IOCTL_GET_MSG _IOW(MAJOR_NUM, 1, char *) 11 | 12 | #endif 13 | -------------------------------------------------------------------------------- /src/null_pointer.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | 5 | static int test_module_init(void) 6 | { 7 | int *p = 1; 8 | printk("%d\n", *p); 9 | return 0; 10 | } 11 | static void test_module_exit(void) 12 | { 13 | return; 14 | } 15 | 16 | module_init(test_module_init); 17 | module_exit(test_module_exit); 18 | -------------------------------------------------------------------------------- /src/timer_hiresolution.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | #include 5 | 6 | MODULE_LICENSE("GPL"); 7 | 8 | #define MS_TO_NS(x) (x * 1E6L) 9 | 10 | static struct hrtimer hr_timer; 11 | 12 | enum hrtimer_restart my_hrtimer_callback( struct hrtimer *timer ) 13 | { 14 | printk( "my_hrtimer_callback called (%ld).\n", jiffies ); 15 | 16 | return HRTIMER_NORESTART; 17 | } 18 | 19 | int init_module( void ) 20 | { 21 | ktime_t ktime; 22 | unsigned long delay_in_ms = 200L; 23 | 24 | printk("HR Timer module installing\n"); 25 | 26 | ktime = ktime_set( 0, MS_TO_NS(delay_in_ms) ); 27 | 28 | hrtimer_init( &hr_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL ); 29 | 30 | hr_timer.function = &my_hrtimer_callback; 31 | 32 | printk( "Starting timer to fire in %ldms (%ld)\n", delay_in_ms, jiffies ); 33 | 34 | hrtimer_start( &hr_timer, ktime, HRTIMER_MODE_REL ); 35 | 36 | return 0; 37 | } 38 | 39 | void cleanup_module( void ) 40 | { 41 | int ret; 42 | 43 | ret = hrtimer_cancel( &hr_timer ); 44 | if (ret) printk("The timer was still in use...\n"); 45 | 46 | printk("HR Timer module uninstalling\n"); 47 | 48 | return; 49 | } 50 | 51 | -------------------------------------------------------------------------------- /src/timer_simple.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | 5 | MODULE_LICENSE("GPL"); 6 | 7 | static struct timer_list my_timer; 8 | 9 | void my_timer_callback( unsigned long data ) 10 | { 11 | printk( "my_timer_callback called (%ld).\n", jiffies ); 12 | } 13 | 14 | int init_module( void ) 15 | { 16 | int ret; 17 | 18 | printk("Timer module installing\n"); 19 | 20 | // my_timer.function, my_timer.data 21 | setup_timer( &my_timer, my_timer_callback, 0 ); 22 | 23 | printk( "Starting timer to fire in 200ms (%ld)\n", jiffies ); 24 | ret = mod_timer( &my_timer, jiffies + msecs_to_jiffies(15000) ); 25 | if (ret) printk("Error in mod_timer\n"); 26 | 27 | return 0; 28 | } 29 | 30 | void cleanup_module( void ) 31 | { 32 | int ret; 33 | /* 34 | ret = del_timer( &my_timer ); 35 | if (ret) printk("The timer is still in use...\n"); 36 | */ 37 | printk("Timer module uninstalling\n"); 38 | 39 | return; 40 | } 41 | 42 | --------------------------------------------------------------------------------